1. Field of the Invention
Embodiments of the present invention relates to systems and methods for optimizing formation fracturing by iteratively optimizing bottom hole pressure (BHP) and temperature design, perforation design, fracturing fluid pulse and rate design, and proppant design based on formation and proppant properties, candidate selection, flow and geomechanical modeling and engineering design.
More particularly, embodiments of the present invention relates to systems and methods for optimizing formation fracturing by iteratively optimizing bottom hole temperature design, perforation design, fracturing fluid pulse and rate design, and proppant design based on formation and proppant properties, candidate selection, flow and geomechanical modeling and engineering design, where the systems include (a) a subsystem that collects or inputs formation and/or zone properties and characteristics, (b) a subsystem that selects a proppant composition, (c) a subsystem that selects fracturing fluid pulses and rates for placing the proppant composition into the formation and/or formation zone, (d) a subsystem that selects a perforation design, (e) a subsystem that selected a bottom hole pressure (BHP) design, and (f) a subsystem that iteratively optimizes proppant composition, fracturing fluid pulse and rate design, perforation design, and BHP design to produce optimal fracturing application parameters based on the formation and/or formation zone and/or proppant properties and characteristics.
2. Description of the Related Art
Hydraulic fracturing is a primary tool for improving well productivity by forming fractures in a formation from a well bore penetrating the formation to enhance production from or injection into the formation. Hydraulic fracturing is typically performed by injecting a fracturing fluid into a wellbore penetrating a subterranean formation above the formation pressure forming or extending cracks and/or fractures in the formation. During the fracturing operation, proppant is also injected into the formation and into the fractures in an attempt to reduce or prevent fracture closing after fracturing, and thus, providing improved flow into and out of the formation or zones thereof.
The success of a hydraulic fracturing treatment is related to the fracture conductivity, which is the ability of fluids to flow from or into the formation through the proppant pack—proppants injected into the fractures to hole the fracture open. In other words, the proppant pack or matrix must have a high fluid conductivity or permeability relative to the formation for fluid to flow with low resistance into or form the wellbore.
In traditional fracturing operations, techniques have been used to increase the fluid conductivity or permeability of the proppant pack by increasing the porosity of the interstitial channels between adjacent proppant particles within the proppant matrix. These traditional operations seek to distribute the porosity and interstitial flow passages as uniformly as possible in the consolidated proppant matrix filling the fracture. The fracturing employs homogeneous proppant placement procedures to substantially uniformly distribute the proppant and non-proppant, porosity-inducing materials within the fractures.
In U.S. Pat. No. 6,776,235 (England), a method for hydraulically fracturing a subterranean formation involving alternating stages of proppant-containing hydraulic fracturing fluids contrasting in their proppant-settling rates to form proppant clusters as pillars that prevent fracture closing to improve hydraulic fracture conductivity. This method can, for example, alternate the stages of proppant-laden and proppant-free fracturing fluids to create proppant clusters in the fractures and open channels between them for formation fluids to flow. Thus, the fracturing treatments result in a heterogeneous proppant placement (HPP) and a “room-and-pillar” configuration in the fractures, rather than a homogeneous proppant placement and consolidated proppant pack. The amount of proppant deposited in the fracture during each HPP stage is modulated by varying the fluid transport characteristics (such as viscosity and elasticity), the proppant densities, diameters, and concentrations and the fracturing fluid injection rate.
In U.S. Pat. No. 7,451,812 (Cooper et al.), a system and a method for heterogeneous proppant placement in a fracture in a subterranean formation are disclosed. The system includes a delivery system for delivering proppant and treatment fluid to the fracture, a sensor for measuring geometry of the fracture and a computer in communication with the sensor. The computer includes a software tool for real-time design of a model for heterogeneous proppant placement in the fracture based on data from the sensor measurements and a software tool for developing and updating a proppant placement schedule for delivering the proppant and treatment fluid to the fracture corresponding to the model. A control link between the computer and the delivery system permits the delivery system to adjust the delivery of the proppant and treatment fluid according the updated proppant placement schedule.
While there are currently a number of systems and methods for modifying or adjusting fracturing operations of a formation, many of these systems and methods suffer from a consideration of only one or two aspects of a fracturing operation, thus, there is a need in the art for systems and methods that are capable of creating an optimal fracturing operation based on formation properties and characteristics by iteratively optimizing all facets/aspects of the fracturing operation.